Questions tagged [relay]

Electrical device which, when energised by a small electrical current (low-power, control circuit), safely switches a larger electrical current (controlled circuit).

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41 views

First steps into controllers and circuits (NOOB ALERT). Why does relay module works only if connected to 5v pin but not with external 5V source?

As title states, I am taking my first steps into electric circuits and microcontrollers, so I apologize in advance if my question is not clear or does not make much sense. I am trying to control ...
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75 views

Wiring 12V 5 pin relay (without a module/board) for usage with Raspberry Pi

I'm trying to setup an automated garden as a quarantine project for my mother and I can't really figure out how to properly wire a 12V 5-pin relay module as every tutorial online only shows the ones ...
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184 views

Issues with Sequent Microsystems 8 relay board

I'm using the Raspberry Pi 3 Model B V1.2, and the Sequent Microsystems 8 Relay Board 2.0. The manual tells you to install this software from github. I installed this and was able to control the ...
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704 views

Relay Bluetooth keyboard out as a USB keyboard

I have a bluetooth keyboard that's originally connected to my desktop PC. The problem is that I can't use it in BIOS or to select different boot options at grub because the bluetooth drivers aren't ...
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0answers
353 views

Issue with lighting 15w bulb using raspberry pi & 8-pin relay

Being naive to hardware & electronics, I might missing something silly here. Here is my setup to able turn on/off bulb using iOS app and node.js as backend - Successfully setup raspberry pi 2 ...
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49 views

GPIO output high not turning of relay

I am trying to turn a relay on and off using a python script. The below script is realy simpel, turn the relay on and after 5 seconds turn it off. The thing is, it dooesn't turn off. i thought it did ...
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27 views

SSR or Opto-Coupler relay only works if shorted

I have a SSR 4 channel relay and an Opto-Coupler one channel relay. Both where specified to work on 3.3V signals. I wrote a quick test program on my raspberrypi zero w and tried both relays with my ...
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244 views

How to cut power to gpio pins on shutdown

I am working on a project where i am using a pi running retropie to make a homemade arcade machine. i have wired and coded a startup/shutdown button. i would like to set up the pi n such a way i can ...
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651 views

RPi.GPIO + single channel relay + solenoid lock

I'm working on my first python/hardware project and I want to create a simple (or at least I thought it was simple) cabinet lock, which will lock/unlock when certain RFID tags are approached to the ...
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340 views

External power supply to a relay controlled by a Raspberry Pi

I am a beginner to relays and Raspberry Pi so please pardon me if my question sounds naive. I am trying to control 4 DC motors using relays and raspberry pi. I have decided to use an external supply ...
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90 views

Relay for controlling backlight of touchscreen not reacting after a while

I connected my rpi3 to a 10" touchscreen. I connected the backlight of the touchscreen to a relay which I'm controlling via the GPIO pins. This is working fine for the first couple of minutes. But ...
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170 views

Issue with Vixen Seq - Pi3 - FPP- relay board

I'm trying to wire my Pi 3B to the relay (octocoupler). I'm wiring the 5V (pin 2 and 4 on the Pi) to the relay, also the grounds. I'm using the following GPIOs from the Pi (Pin numbers): 7(GPIO4)-11(...
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243 views

rPi 3b only boots with 5v power through the 3.3v GPIO

I'm in need of some explanation as my Pi is acting weird (to my limited knowledge at least) It will only boot when i suply it with 5v/GND through the 3.3/GND GPIOs. The pi boots when i connect 5v ...
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738 views

Controlling power to a raspberry pi with relay or MOSFETs

So I have a 12V battery connected to a (5v/6v optional) UBEC powering the pi through the GPIO pins. Using a separate circuit, probably with a micro-controller, I want to be able to toggle power to ...
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192 views

raspberry pi relay switch to ouput bulbs/other devices diagram

I'm new to raspberry pi, need some advise on the raspberry pi 2 to relay switch diagram which output to bulbs/other devices. The attach screenshot only connects from the pi to relay switch, but stuck ...
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2k views

rPi model B + MCP23017 + relay board. GPA0 pin low output not close enough to 0v to trigger relay

I've setup a MCP23017 16-bit I/O expander with a rPi model B via i2c, and I am able to control components like LEDs on the channels GPA0-GPA7 using code like this; # set GPA pins to output i2cset -y ...
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1answer
421 views

Monitoring a Generator, Send email per relay state

I need to monitor the state of a generator. When the generator turns on ( testing or power failure) there is a relay that goes high/low. I can read from either state. I need for the pi to send email ...
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14 views

GPIO change state record

I'm looking for a way to record Datetime and state of GPIO, but just want a record when the state change. I have this in my code: temp_def = 30.0 while True: print(read_temp()) if(read_temp() &...
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2answers
36 views

Raspberry Pi 4 GPIOs are constantly on, even after restarting and cleaning up GPIOs

So, I got a Raspberry Pi 4 Model B, and I'm trying to make a project using relay boards. Turns out, when I turn on my Pi, one of the pins is already active and the indicator turned on partially. I ...
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1answer
68 views

16 module relay board connection to RPi Zero W

I am using raspberry pi zero W for a home automation project. I am using 5V 16 channel relay board and using all the 16 relays as part of the project. I have not connected a separate 5V power supply ...
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1answer
462 views

How to control raspberry pi 4 GPIO pins by running android application in the rpi and in mobile?

I am trying to build a project based on IoT. My goal is to trigger relays connected to GPIO pins in rpi4 by using an android application running in rpi4 itself which can be accessed with an official ...
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38 views

3.3v Relay switches on/off/on - off fails 2nd switch off

This 3.3v .relay, link to the the >>> Datasheet As the title mentions works fine until I try to switch it off the second time round, I see the red LED turning on (it looks a touch dim) ...
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51 views

Raspberry PI and 8 module relay board

I have a raspberry pi 2 and an 8 module relay board (http://nettop.gr/index.php/en/hlektronika/relay/8-channel-5v-relay-module-with-light-coupling-5v.html). Between the relay board and the raspberry I ...
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40 views

Relay is behaving differently from tutorial

Given: Raspberry Pi3 Sunfounder 2 channel relay plugged into 3.3v plugged into ground plugged into pin 18 import RPi.GPIO as GPIO import time GPIO.setmode(GPIO.BCM) GPIO.setup(18, GPIO.OUT) GPIO....
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183 views

GPIO Power off on shutdown with retropie

i asked this question before but i have added a diagram to explain it more clearly. I am building a retropie arcade machine with a raspberry pi. I have added a shutdown / startup button to shutdown ...
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644 views

Rpi3 Home Assistant To Read Signals at GPIO Pins Problem

I'm really new to Raspberry Pi, so please forgive me if this is a noobish question. I have a very simple setup: Raspberry Pi 3 running Home Assistant with a switch connected to GPIO12 and 3.3v. The ...
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30 views

Powering solenoid from batterypack

Im trying to power my 6V solenoid that is connected to my 8 channel 5V relay using my 8 x AA batterypack. The pi is being powered through an adapter and the relay from the VCC to 5V pi. When the LED ...
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173 views

using Pi Zero W GPIO relay control

I am trying to control my relay with Raspberry GPIO. Using the terminal to write to gpio5 (Physical 18, BCM 24) works: gpio mode 5 out gpio write 5 1 Trying to do the same in my c++ code doesn't ...
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143 views

Connecting a PIR and Relay Module to a Raspberry Pi causing 2 Minute False Alarms

I am building a small home automation system, and one node has a PIR to detect motion, and a Relay Module to control a 240v light with a Raspberry PI 3. The PIR is connected to 5v, and has a ...
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148 views

Raspberry Pi's Ethernet cable port suddenly stopped working after connecting 4-channel Relay board

I am having trouble with my Raspberry Pi's Ethernet and USB ports. I was using Ethernet port usually for my experiments with pi. But I tried to connect 4-channel relay board to my pi. According to my ...
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2answers
175 views

Small pulses - DHT11 relay triger

I'd like to trigger my relay to turn on my lamp when the humidity level measured is greater than 85. Here's the code I've been using. import Adafruit_DHT import RPi.GPIO as GPIO import time sensor = ...
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68 views

Sync 5 Raspberry Pi3 B+

Hi I'm new to programming and Raspberry Pi. What I am looking for is what platform I need to play in sync a unique video-loop for each RPi (off a USB). I have installed Raspian. Each is connected to ...
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547 views

How can a simple NPN step up from 3.3 to 5, without 5V in picture?

I've come across this circuit to common pi problem of stepping up 3.3 GPIO to 5V, so it could drive a relay module (Link here). I've one doubt, most circuits online also have a 5V input in the circuit,...
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769 views

Relay and Raspberry Pi connection advice?

I have read quite a few threads regarding this same subject with varying answers.I plan on using the relay to turn on and off a 3d printer.I have read a few threads stating that the 3.3v from the ...
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536 views

Relay attached to GPIO pin gets "stuck" after switching

So this seems odd to me, I am using a 4-relay module 2 of these relays attached to GPIOs 7 and 0 (Header pins 7 and 11 respectively on a Raspberry Pi B 2). Mains AC is passing through relay 2 using ...
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241 views

Unable to set GPIO.HIGH. GPIO.LOW

I am trying to control a relay with Pi3B. Whenever I run GPIO.setup(port, GPIO.OUT) my relay starts working, then any other command I try, eg. GPIO.output(port, GPIO.HIGH) or GPIO.output(port, GPIO....
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325 views

(PI3) GPIO pin stay high, even after set to low

I'm trying to turn on and off relay using raspberry pi 3. But after successfully turn on, it will stay on even after I set GPIO pin to low. I use pi4j example and python example, both of them give me ...
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1answer
103 views

Piface Digital Master and PiFace Relay Plus Slave

I wish to control four state reconfigurable antennas in a propagation measurements using RPis at both ends of the propagation channel. The headless master RPi has a PiFace digital to control the start ...
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2answers
509 views

Suggestions to monitor mains voltage from a heating stat

Does anyone have a good idea for monitoring if a wire is live 240v or not. I'm wiring a PI relay in parallel with the room stats (8 stats in total) so that either the room stat or the relevant pi ...
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596 views

Raspberry Pi B+ relay state reading via GPIO pin

I have working system with Raspberry Pi B+ and 7 relays (via ULN2003A to provide 12V to relay coil) connected to it via GPIO pins. That is all ok (working perfectly), but now I would like to read ...
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1answer
951 views

Controlling High voltage devices with Raspberry Pi

Can I control high voltage (here 5V) to power a led lamp and a fan(both operating at 5v) from Raspberry Pi GPIO only using a transistor . Or should I isolate both the circuits using a relay or octo-...
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1answer
377 views

Why is my GPIO not switching my attached relay?

I have a relay attached to a Raspberry Pi B+ GPIO via two wires, one wire is attached to physical pin 6, a ground pin, the other is attached to physical pin 15 (GPIO. 3, BCM 22, wPi 3). I have a 2 ...
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1answer
40 views

Relay provides power contineously

I have set up a Pi-Zero which controls several relay switches. The Schematic is positioned below. import time import board import busio import digitalio from board import * from datetime import date ...
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2answers
90 views

Can a Relay Module be powered by the GPIO pin or do I need DC adaptor?

I have a 5 V 10 Amp relay module and a Raspberry Pi 3. I am using it to connect to a submersible pump which runs on AC power. Can I use the 5 V GPIO pin of the Raspberry Pi or do I need to buy a DC ...
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2answers
201 views

Traditional Light Switch Triggered by RPi?

Does anyone know of a light switch which can be controlled using the RPi and also manually. Assuming that the RPi sends a signal thru a relay which connects to the light switch. The switch will turn ...
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2answers
473 views

5V Relay only works if VCC is 3.3V

I am very new to all of this, so please excuse if this is a very basic question. I am trying to power a tiny water pump with my raspberry pi. For that I need the 3.3V or 5V output, because the GPIO ...